Investigating a Systematic and Widespread Misidentification in the Metabolic Profiling Literature: Phenylacetylglutamine and Phenylacetylglycine Signal Misassignment in Proton NMR Spectra of Human and Rodent Urine.

ABSTRACT: Accurate assignment of endogenous and exogenous constituents within complex biological matrices remains a central challenge in metabolomics. Phenylacetylglutamine (PAGln) and phenylacetylglycine (PAGly) are terminal metabolites of the host-microbial co metabolism of phenylalanine, predominantly observed in humans and rodents, respectively. Motivated by a pervasive misidentification within the literature, we demonstrate that PAGln in human urine has been erroneously identified as PAGly in 82 of 166 NMR-based studies, yielding an estimated misannotation rate of 49%. Herein, we provide definitive assignments for both PAGly and PAGln, and present a comprehensive statistical evaluation of the NMR resonances attributed to both species, alongside their quantitative determination via targeted line

SUBMITTER: Sala S 

PROVIDER: S-EPMC12646498 | biostudies-literature | 2025 Nov

REPOSITORIES: biostudies-literature